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Potassium chloride, KCl, is an ionic compound containing potassium ions, K⁺, and chloride ions, Cl⁻ - OCR Gateway - GCSE Chemistry: Combined Science - Question 17 - 2020 - Paper 1
Question 17
Potassium chloride, KCl, is an ionic compound containing potassium ions, K⁺, and chloride ions, Cl⁻. Potassium chloride can be electrolysed when it is a molten liqu... show full transcript
Worked Solution & Example Answer:Potassium chloride, KCl, is an ionic compound containing potassium ions, K⁺, and chloride ions, Cl⁻ - OCR Gateway - GCSE Chemistry: Combined Science - Question 17 - 2020 - Paper 1
Step 1
Explain the term electrolysis.
Answer
Electrolysis is a chemical process that uses electrical energy to induce a non-spontaneous chemical reaction. It involves the breakdown of an ionic compound into its constituent ions when an electric current passes through a molten or aqueous solution of the compound. During electrolysis, the positively charged ions (cations) migrate to the cathode (negative electrode) to gain electrons, while the negatively charged ions (anions) move towards the anode (positive electrode) to lose electrons.
Step 2
Describe the difference between cations and anions.
Answer
Cations are positively charged ions that are formed when an atom loses one or more electrons. They migrate towards the cathode during electrolysis. In contrast, anions are negatively charged ions that form when an atom gains one or more electrons. Anions migrate towards the anode in the electrolysis process.
Step 3
Step 4
State and explain if this equation shows oxidation or reduction.
Answer
The equation shows reduction. Reduction is the process where a species gains electrons, leading to a decrease in oxidation state. In this case, the potassium ion (K⁺) gains an electron (e⁻) to form neutral potassium (K), which results in a reduction of its oxidation state from +1 to 0.